PyNormaliz - An interface to Normaliz

What is PyNormaliz

PyNormaliz provides an interface to Normaliz (https://www.normaliz.uni-osnabrueck.de) via libNormaliz. It offers the complete functionality of Normaliz, and can be used interactively from python. For a first example, see this introduction by Richard Sieg.

Requirements

• python 2.7 or higher or python 3.4 or higher
• Normaliz 3.2.1 or higher (https://github.com/Normaliz/Normaliz/releases)

The source packages of the Normaliz realeases contains PyNormaliz.

Installation

The PyNormaliz install script assumes that you have executed the

install_normaliz_with_qnormaliz_eantic.sh

script. To install PyNormaliz and navigate to the Normaliz directory and type

python setup.py install --user

The script can be customized by some options. See Appendix E of the Normaliz manual.

Usage

The main command is Cone to create a cone, and the member functions of the cone class to compute properties. For a full list of input and output properties, see the Normaliz manual.

To create a cone, use

import PyNormaliz
C = PyNormaliz.Cone(cone = [[1,0],[0,1]])

All possible Normaliz input types can be given as keyword arguments.

To compute a property of the cone, use the provided getters, which correspond to Normaliz computation goals.

C.HilbertBasis()

You can pass options to the compute functions

C.HilbertSeries(HSOP = True)

Low level commands

There is also a low-level API, directly using C functions:

To create a cone, use

C = NmzCone("cone", [[1,0],[0,1]])

or, equivalently,

C = NmzCone(["cone", [[1,0],[0,1]]])

NmzCone can take an arbitrary number of arguments, either as separated arguments or in a list. First is always a string, describing an input property for Normaliz, followed by a (possibly empty) matrix.

NmzCompute takes a cone as first argument, followed by arbitrary many strings, or a list of strings, describing Normaliz output types. NmzCompute lets Normaliz compute the necessary values, and returns true if everything was computed properly, false otherwise.

NmzCompute(C, "HilbertBasis")

or

NmzCompute(C, ["HilbertBasis"])

NmzIsComputed takes a cone and a string representing an output property, and returns true if the property is already computed for the cone, false otherwise. (In contrast to NmzCompute it does not start a computation.)

NmzIsComputed(C, "HilbertBasis")

NmzResult takes a cone and a string representing an output property, and returns the computed value of this property as a matrix, a list, or as a bool.

NmzResult(C, "HilbertBasis")